Sheldon Cooper’s 73 Shirt

Sheldon’s 73 Shirt can be seen on Dr. Sheldon Cooper on the Big Bang Theory.

The 73 reference is from Season 4, Episode 10 (The Alien Parasite Hypothesis), when Sheldon says “The best number is 73…. 73 is the twenty-first prime number. Its mirror, 37, is the twelfth and its mirror, 21, is the product of multiplying (hang on to your hats) 7 and 3…. In binary, 73 is a palindrome: 1-0-0-1-0-0-1, which backwards is 1-0-0-1-0-0-1.”

Jim Parsons was born in the year 1973. “The Alien Parasite Hypothesis” is the 73rd episode of The Big Bang Theory.